Time-limit circuit-breaker.



UNITED STATES PATENT OFFICE.

HALFDAN A. STEEN, OF MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNEASSIGNMENTS,

TO ALLIS-CHALMERS MANUFACTURING COMPANY, A CORPORATION OF DELAWARE.

TIME-LIMIT CIRCUIT-BREAKER.

Application filed April 8, 1911.

To all whom it may concern:

Be it known that I, HALFDAN A. STEEN, a subject of the King of Norway,residing at Milwaukee, in the county of Milwaukee and State ofWisconsin, have invented certain new and useful Improvements in Time-Limit Circuit-Breakers, of which the following is a full, clear, andexact specification.

This invention relates to time element devices for electric switches.

In controlling electric apparatus it is very often desired that the timeof a required operation shall be delayed for an appreciable intervalafter a change of condition occurs. For example, when a circuit isovertaxed with current it would occasion considerable annoyance if thecircuit were always immediately open, for the reason that the apparatusis not endangered by a brief interval of overload. Also when there is anaccidental ground it is undesirable to open the circuit unless theground be of an enduring character. For these reasons'there is oftenemployed a time element device for retarding the operation of electricswitches under abnormal circuit conditions which may be momentary or ofan enduring character, in which latter case the endangered circuit willbe opened within a safe limit.

The object of my invention is to provide an improved time element devicefor the purposes above set forth.

The various novel features of this invention will be described in thespecification and particularly set forth in the appended claims.

The invention is illustrated on the accompanying sheet of drawings, inwhich Figure 1 is a partial diagrammatic view showing a generatorcircuit provided with a circuit-breaker in combination with my improvedtime element device. Fig. 2 is a front elevation of a modification ofthe above time element device shown submerged in a liquid; and, Fig. 3is a front elevation of the device shown in Fig. 2, the device beingpartially above the surface of the liquid.

A generator 10, here shown as having a shunt field 11, and mains 10 and10 is provided with a line switch 12 and an automatically operatedcircuit-breaker 13. The circuit-breaker includes an arm 14: and link 15between which is mounted a normally energized spring 16 adapted to openthe circuit-breaker upon certain predetermined Specification of LettersPatent.

Patented May 18, 1915.

Serial No. 619,692.

circuit conditions. The arm 14 is pivoted to a lug 17 of a liquidcontaining tank 18, and is held in circuit-closing position by havingits upper end 19 engage a notched portion 20 of a trigger 21. Thispivotally mounted trigger 21 is adapted to be raised out of engagementwith the upper portion 19 of arm 11 by a rod 22 connected to a movablecore 23. The core 23 is adapted to be actuated upon the occurrence ofcertain predetermined abnormal circuit conditions by a solenoid 24:which is included in the generator circuit. Fixed to the rod 22 is acap-shaped suction member 25 having a leak valve 26 and another valve27. Located within the tank 18 is a quantity of liquid 28, preferablyoil, in which the core 23, coil 2A, and suction member are submerged.The suction member, under certain conditions, is actuated in and raisedout of the liquid 28. For example, if an overload on the generatorcircuit arises, the solenoid 2 1 will be suificiently energized to raisethe core 23 and suction member 25. Due to the friction of the oil theupward movement of the suction member will be somewhat retarded. Thisretarded movement will continue even after the upper portion of thesuction member is raised above the level 29 of the liquid on account ofthe suction member still retaining the liquid after it is raised abovethe normal level of the liquid in the tank. Due to the action of thesuction member after it is raised partially out of the liquid 28, theliquid Within the suction member is maintained higher than the level ofthe liquid in the tank 18. In other words, the liquid in the suctionmember is unable to escape rapidly enough to keep its level the same asthat of the level of the liquid in the tank. WVith the suction memberpartially out of the liquid, air passes through the leak valve 26,thereby gradually forcing out the liquid within the suction member andthus providing for the continued retarded upward movement of the rod 22.If the overload is one of a temporary character the rod 22 will not beraised sufliciently to engage the trigger 21. But if the overload is ofan enduring character the rod 22 will pass into engagement with thetrigger 21 raising it out of engagement with the arm 14, whereupon, dueto the action of the spring 16 the switch or circuit-breaker 13 iscollapsed, breaking the circuit. It is therefore seen that a meretemporary overload Will not be sufiicient to operate thecircuit-breaker, but if the overload continues a certain predeterminedtime the circuit-breaker Will be operated. When the overload on thegenerator circuit discontinues, the rod 22 is permitted to return to itsnormal position much quicker than it was raised for the reason that thevalve 27 will be opened providing for the passage of a comparativelylarge volume of liquid in a short time. The rod 22, which is guided inthe cap 30 of the tank 18, is held in its normal position by a collar 31which engages the cap 30.

In Figs. 2 and 3 a modification of the time element or suction deviceillustrated in Fig. 1 is shown. Here, instead of using a shallowcap-shaped suction member, a deep cap-shaped suction member 32 isprovided which also has a leak valve 33 and valve 3 1 for a quick returnmovement. This suction member 32 is provided with diametrically oppositeslots 35 and also with an adjustable collar 36 which is adapted to bemoved lengthwise of the shell 32 for varying the effective duration ofthe time limit. The suction member 32 acts precisely the same as member25 with the exception that it provides for a longer or greater retardingeffect and is also provided with adjustable means for varying the lengthof the retarded effect. When the suction member 32 is raised partiallyout 01 the liquid the retardation of the upward movement continues untilthe cap has raised to such an extent, as shown in Fig. 3, that the slots35 have reached the level of the liquid in the tank 18, whereupon therod shoots upward rapidly to trip the circuit-breaker.

This time element device is not only applicable for use as hereillustrated, but can be applied wherever the use of a retardation ortime element device is desirable.

There may be many modifications in the precise form and arrangement hereshown and described, and I aim to cover all such modifications which donot depart from the spirit and scope of my invention, as set forth inthe appended claims.

What I claim as new is:

1. A time element device comprising a receptacle containing a liquid, amovable member disposed outside of said casing, an electromagnet in saidcasing, the core of said magnet having a projection extending throughsaid casing and movable into engagement with said movable member toactuate the same, and a suction member normally immersed in said liquidand movable by said core out of said liquid, said suction member beingprovided with a leak opening permitting the equalization of pressureswithin and. without the suction member.

2. In combination, a receptacle partly filled with liquid, a cover forsaid receptacle, a movable member disposed outside said receptacle, anelectromagnet having a coil and a core therefor mounted in saidreceptacle, a suction member normally immersed in said liquid andmovable with said core, said suction member comprising a hollow elementclosed at its upper end and provided with a restricted opening betweenits upper and under sides and with means for varying the depth of theimperforate portion of said hollow element below said restrictedopening, and an extension from said core passing through said cover andengageable with said movable member to actuate the same.

Milwaukee, lVis, April 3, 1911.

In testimony whereof I ailix my signature, in the presence of twowitnesses.

HALFDAN A. STEEN. lVitnesses CHAS. L. BYRON, Roe. E. S'roLL.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

